Normally, the CoApp tools use an .autopkg file rather than a .nuspec file to contain the instructions for building the package. In the Appveyor environment, this has one small drawback. Since the package is built on each push to the underlying code repository, multiple builds will happen with the same version number in the .autopkg file. This causes deployment to fail, as a package cannot be uploaded with the same version number as the existing package.

To solve this, the .autopkg file can be renamed to .autopkg.template, and a placeholder used where the version number should go. The Appveyor build process can then replace this placeholder with the build number, ensuring the generated .autopkg file always has a unique, incrementing version number.